The present invention relates to closures for sealing containers and specifically to cork or stopper for carbonated beverages such as champagne having novel features of construction and arrangement providing a tight tamper evident seal and including easily actuatable venting means for safely releasing internal pressure in the container before removing the closure.
Containers for certain carbonated beverages have to be sealed tightly so that they retain a certain amount of gas pressure generated as a beneficial or inherent feature of the product. Typically, when opening these containers for discharge of the product, the pressure within the container will be reduced to atmospheric and it is therefore also important to be able to control the initial release of gas pressure which resides in the head space between the closure and the product. If the pressure is released instantaneously, the force may be expanded to cause spraying product from the mouth of the container which is undesirable and may in some instances propel the closure which is typically a cork as a projectile which can cause injury to the user.
Venting type closures for containers are not new, per se. For example, the Luczak, et al. U.S. Pat. No. 3,717,276 shows a multi-piece closure for pressurized carbonated beverages and the like. The closure construction essentially comprises a plastic liner which seals the mouth of the container, an outer metal cap provided with a pull tab for a removable tear strip and a skirt which crimps under the container finish to seat and seal the liner against the container opening. An aperture in the liner provides a vent hole communicating with the interior of the container. There is also a network of vent channels in the liner in the form of radial grooves and an annular groove connecting the radial legs adjacent the skirt of the cap which normally are sealed by the metal cap about the periphery of the container opening by the crimped skirt. A tear strip is formed in the top panel of the cap across the corner radius and skirt by a continuous score line. The score line will increase the tendency of the metal to shear along that line so that the strip may be peeled back by a pull tab or ring fastened to the tear strip by a rivet near the forward end of the tear strip. It has been found that due to glass finish imperfections and non-uniform crimping action, there may develop small leakage paths permitting venting prematurely. This is, of course, harmful in the case of carbonated beverages like champagne since the product must be maintained pressurized until ready for consumption. Furthermore, the closure is not truly tamperproof by visual examination since there is the possibility of slight lifting of the skirt of the outer cap with an instrument creating a venting path to the interior of the container through the vent channels in the linear and central opening in the liner in direct flow communication with the channels. Lastly, this closure can be prematurely activated to produce a venting action if the pull tab is actuated inadvertently.
There are other closure assemblies which are also of interest. For example, the Smythe U.S. Pat. No. 248,360, issued Oct. 18, 1881, shows a cork with a passageway that mounts a filter. Ludamen, U.S. Pat. No. 329,920, issued Nov. 10, 1885, shows a bottle stopper. In one form of the invention, the stopper has a severable portion which is cone-shaped and normally seals the bottle discharge opening. The user severs the cone-shaped top to permit the discharge of contents and then inverts the cap to stopper the opening for temporary closures during storage and the like. Haldig, U.S. Pat. No. 1,502,775, issued July 29, 1924 shows a safety closure for pressurized vessels simply consisting of a cork having a very narrow central opening that communicates with the contents and a paper disc for normally sealing the opening in the core. The opening is of a capillary dimension to prevent the loss of fluid from the container. However, if internal pressures develop as a result of fermentation, the pressure bursts the paper rather than blowing the cork.
With the foregoing in mind, it is an object of the present invention to provide a relatively simple and economical venting closure for containers for carbonated beverages and the like which effectively seals the container prior to use and is easy to manipulate to release the pressure in a hazard free manner.
Another object of the present invention is to provide a two piece closure with such venting function that is simple, efficient, easy and economical to assemble and operate.